Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
234 words
A DC-DC converter comprising two DC voltage input terminals to which a supply voltage is applied and between which a series connection of a primary winding of the converter transformer and a main semiconductor switching element are arranged, while between the junction of said primary winding and main semiconductor switching element on the one hand and the positive and/or negative supply terminal on the other, one or more resonant capacitors are arranged, while the transformer further comprises one or more secondary winding(s) with which rectifiers and smoothing capacitors are connected, while loads can be connected to the smoothing capacitors, with the secondary winding(s) being deliberately coupled poorly with the primary winding, and the rectifiers being so arranged that they are in the conductive state when the main semiconductor switching element is in the non-conductive state, characterized in that at least a series connection of at least one auxiliary semiconductor switching element (5) and at least one clip capacitor (6) is arranged, which is connected on the one hand with one of the supply terminals and on the other hand with the junction of the primary winding and the main semiconductor switching element or with a branch of the primary winding or with a separate winding which is properly coupled with the primary winding, the main semiconductor switching element and the auxiliary semiconductor switching element being alternately and in non-overlapping manner in the conductive state.
Claim 2
Dependent Claim
31 words
A converter according to claim 1, characterized in that the clip capacitor comprises two or more capacitors, which are each connected with one connection to the positive and/or negative supply terminal.
Claim 3
Dependent Claim
130 words
A converter according to claim 1 or 2, characterized in that the converter is so dimensioned that under all load conditions, including short-circuiting of the output terminals and input voltages which can occur in operation, the auxiliary semiconductor switching element does not enter the conductive state until the voltage across the auxiliary semiconductor switching element has oscillated back to zero or at least to a voltage which is much lower than the supply voltage, and that the main semiconductor switching element is not brought into the conductive state until the voltage across it has oscillated back at least to a voltage which is much lower than the supply voltage, so that both for the auxiliary semiconductor switching element and for the main semiconductor switching element mainly "zero-voltage switching" is used.
Claim 4
Dependent Claim
43 words
A converter according to claim 1, 2, or 3, characterized in that the transmitted power of the converter is controllable by means of the current level at which the main semiconductor switching element (21) is brought into the non-conductive state (current mode control).
Claim 5
Dependent Claim
45 words
A converter according to claim 4, characterized in that the peak voltage across the primary winding of the converter transformer in the conduction period of the auxiliary semiconductor switching element is controllable by means of the duration of conduction of the auxiliary semiconductor switching element.
Claim 6
Dependent Claim
52 words
A converter according to claim 5, arranged to provide a stabilized output voltage, characterized in that means are provided for simultaneously influencing the value of the current at which the main semiconductor switching element is switched off and the level of the peak voltage across the primary winding of the converter transformer.